On Sun, 30 Nov 2014, Lino Sanfilippo wrote:
> On 29.11.2014 19:00, SF Markus Elfring wrote: > > > out: > > - if (mac->iob_pdev) > > - pci_dev_put(mac->iob_pdev); > > - if (mac->dma_pdev) > > - pci_dev_put(mac->dma_pdev); > > + pci_dev_put(mac->iob_pdev); > > + pci_dev_put(mac->dma_pdev); > > > > free_netdev(dev); > > out_disable_device: > > > > Hi, > > I know there has been some criticism about those kind of "code > improvements" already but i would like to point out just one more thing: > > Some of those NULL pointer checks on input parameters may have been > added subsequently to functions. So there may be older kernel versions > out there in which those checks dont exists in some cases. If some of > the now "cleaned up" code is backported to such a kernel chances are > good that those missing checks are overseen. And then neither caller nor > callee is doing the NULL pointer check. > > Quite frankly i would vote for the opposite approach: Never rely on the > callee do to checks for NULL and do it always in the caller. An > exception could be for calls on a fast path. But most of those checks > are done on error paths anyway. I have heard of at least one case where the problem you are raising happened in practice... julia -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
